People have made lots of good suggestions. DocVikingo, as usual, has given some particularly good advice. Cozumel is probably your best bet for getting the trip in for less than $2500. The diving is excellent and it's fun topside as well. For your non-diving days, you can take the ferry across the channel to Playa del Carmen. From there, you can just hang around Playa, which is a fun place, or use it as a jumping off point to visit Mayan archaelogical sites (Chichen Itza, Coba, Tulum), tourist attractions in the Riviera Maya, or do any number of things. Cozumel is about the only place in the Caribbean we can get to in one hop from places like Michigan and Ohio. You can pick up package deals for about the price you mentioned. In addition to the other travel sites, you can get well-priced packages from Apple Vacations, Funjet, and some other consolidators. Bonaire and Curacao can be difficult to get to and the airfare can be pretty expensive.
Another option is to fly into Cancun and stay in Playa or somewhere else in the Riviera Maya. The diving is not as good as Cozumel, but it's decent. You can usually get good airfare into Cancun and there is a good selection of hotels and resorts in Playa and the Riviera Maya. Check out Hotel La Tortuga in Playa. Tank Ha is a good dive shop in Playa. You might stand an even better chance of keeping the trip in your budget in Playa.
Another option is to fly into Cancun and stay in Playa or somewhere else in the Riviera Maya. The diving is not as good as Cozumel, but it's decent. You can usually get good airfare into Cancun and there is a good selection of hotels and resorts in Playa and the Riviera Maya. Check out Hotel La Tortuga in Playa. Tank Ha is a good dive shop in Playa. You might stand an even better chance of keeping the trip in your budget in Playa.
